RPR networks provide robust and efficient packet networking over a fiber ring topology. RPR technology is defined in IEEE Standard 802.17. This technology incorporates extensive performance monitoring, proactive network restoration, and flexible deployment capabilities. RPR networks have the ability to carry multiple services, including jitter- and latency-sensitive traffic (such as voice and video), as well as Ethernet and Internet protocol (IP) traffic. RPR technology combines the best features of legacy synchronous optical network (SONET)/synchronous digital hierarchy (SDH) networks and Ethernet networks into one layer to maximize network efficiency while delivering carrier-class service.
RPR networks are optimized to transport data traffic rather than circuit-based traffic. This packet transport, with bandwidth consumed only between source and destination nodes, is more efficient than a time division multiplexing (TDM) transport such as SONET/SDH. RPR also offers the ability to differentiate and provide improved service for jitter- and latency-sensitive traffic on the ring.
One of the advantages of RPR is its ability to provide spatial reuse in a ring network. For example, traffic can be communicated between two stations on the RPR ring without the traffic traveling around the entire ring. Thus, other segments of the ring may be used to transmit other traffic. However, such spatial reuse is often not possible in situations where traffic to or from a location remote to the network needs to be sent between stations on the RPR network. For example, local area network (LAN) traffic may be bridged across the RPR network. In such a case, the traffic may need to be “flooded” over the network for delivery to the intended destination, thus defeating spatial reuse and the associated network efficiency improvements.